<!DOCTYPE html>
<html>
<head>
    <title>Redux basic example</title>
    <script src="https://unpkg.com/redux@latest/dist/redux.min.js"></script>
</head>
<body>
<div>
    <p>
        Clicked: <span id="value">0</span> times
        <button id="increment">+</button>
        <button id="decrement">-</button>
        <button id="incrementIfOdd">Increment if odd</button>
        <button id="incrementAsync">Increment async</button>
    </p>
</div>
<script>
    function counter(state, action) {
        if (typeof state === 'undefined') {
            return 0
        }

        switch (action.type) {
            case 'INCREMENT':
                return state + 1
            case 'DECREMENT':
                return state - 1
            default:
                return state
        }
    }

    var store = Redux.createStore(counter)
    var valueEl = document.getElementById('value')

    function render() {
        valueEl.innerHTML = store.getState().toString()
    }

    render()
    store.subscribe(render)

    document.getElementById('increment')
        .addEventListener('click', function () {
            store.dispatch({ type: 'INCREMENT' })
        })

    document.getElementById('decrement')
        .addEventListener('click', function () {
            store.dispatch({ type: 'DECREMENT' })
        })

    document.getElementById('incrementIfOdd')
        .addEventListener('click', function () {
            if (store.getState() % 2 !== 0) {
                store.dispatch({ type: 'INCREMENT' })
            }
        })

    document.getElementById('incrementAsync')
        .addEventListener('click', function () {
            setTimeout(function () {
                store.dispatch({ type: 'INCREMENT' })
            }, 1000)
        })
</script>
</body>
</html>
